Weighing-scale.



A. S. DYSART.

WEIGHING SCALE.

APPLICATION FILED oEc.2e.1914.

1,21 5,638. Patented Feb. 13, 1917.

3 Z7 3 flllllllllfi'%l h WITNESSES INVENTOR A NORA/E Y8 UNITED STATESPATENT OFFICE. I

ARTHUR SAMUEL DYSART, OF NORFOLK, VIRGINIA.

WEIGHING-SCALE.

Application filed December 26, 1914.

To all whom it may concern:

Be it known that I, ARTHUR S. DYSART, a citizen of the United States,and a resident of Norfolk, in the county of Norfolk and State ofVirginia, have made certain new and useful Improvements in VVeighing-Scales, of which the following is a specification.

This invention relates to weighing scales and more particularly to thatclass of scales in which the reactional force counterbalancing theweight of an object is supplied by the buoyant effect of a liquid.

An object of the present invention is to provide a scale totally devoidof resilient springs, and in lieu thereof to provide a member immersedin a liquid, the buoyant effect of the liquid upon the member supplyingthe reactional force for the counterbalancing of the object to beweighed.

A further object is to provide means whereby a change in the specificdensity of the liquid employed in accordance with temperatures, iscompensated for.

A further object is to provide a scale of the class mentioned with acoin releasing mechanism so that the scale may be used for publicweighing.

A further object is to provide a movably mounted dial and pointer, thearrangement being such that the scale reading will indicate the positionof the weighing beam regardless of the height of liquid in which thecounterbalancing member is immersed.

With the foregoing and other objects in view which will appear as thedescription proceeds, the invention resides inthe combination andarrangements of parts and in the details of construction hereinafter described and claimed, it being understood that changes in the preciseembodiment of the invention herein disclosed, can be made within thescope of what isclaimed without departing from the spirit of theinvention.

In the drawings accompanying this specification and forming a partthereof, the preferred embodiment of my invention is illustrated, inwhich Figure 1 is a view in elevation of my novel weighing scale.

Specification of Letters Patent.

Patented Feb. 13, 1917.

Serial No. 879,076.

Fig. 2 is a cross sectional view taken on line 2-2 of Fig. 1.

Fig. 3 is a detail view in perspective of the coin controlled mechanism.

Fig. 4 is a view in elevation of a somewhat modified form of scale.

Fig. 5 is a detail side view of the revolving disk and pointer used inconnection therewith looking at Fig. 4 in the direction of the arrow.

Fig. 6 is a view in perspective of the scale beam.

Referring to the drawings in which similar reference numerals designatecorresponding parts throughout the several views, a scale beam 1 isfulcrumed at its one extremity and so supported by the bearing 2. A link3 is pivotally secured to the scale beam and is adapted to connect thesame to the platform of a weighing scale or allied apparatus whoseweight is to be determined.

The linkage 3 will accordingly exert a force upon the scale beam 1 in adownward direction and in order to provide an indicating andcounterbalancing mechanism the elongated reservoir 4 is provided inwhich reciprocates the buoyant tube 5. The tube 5 is provided with theoutstanding lugs 6 thus maintaining the tube and reservoir in spacedsliding relation. The tube 5 is closed at its lower extremity and isimmersed. in a liquid 7 of known density. A bracket 8 is secured to theupper and exposed extremity of the buoyant member 5 and is pivotallyconnected to the scale beam 1 by the linkage 9 thus the moving of thescale beam 1 will produce a corresponding motion of the buoyant member.The immersed buoyont member 5 closely approximates in size the internaldiameter of the reservoir so that although a sliding action may takeplace in a free and unrestricted manner only slight clearance will behad therebetween thus a slight motion of the buoyant plunger 5 willcause a large change in the height of liquid within the reservoir,producing a proportionally large change in the counterbalancing effectapplied to the scale beam. The buoyant plunger is, in the use ofmercury, provided with a longitudinal groove or depression 10 so thatthe liquid will, on account of its negative capillarity, rise to agreater height in the slot than elsewhere allowing the scales 11 whichare arranged along the sides of the slot to be easily read.

ln order that the scales may be used for public weighing thecoinreleasing mechanism 12 is provided, the same including the coinreceiving and delivering tube 13 at the lower extremity of which isplaced the counter-weighted door 1% to which a link 15 is pivotall ysecured. A lever 16 is connected to and actlilated by the link 15 andacts in the capacity of a pawl engaging the ratchet teeth 17 formed onthe ratchet bar 18. The ratchet bar is carried by the scale beam 1 andis provided with downwardly depending ratchet teeth 17 arranged abovethe scale beam and the upwardly extending ratchet teeth 19 arrangedbelow the scale beam. The pawl 16 is adapted to en age the ratchet teeth1.7 and when so positioned prevent the downward motion of the scale beamand therefore prevent weighing of any object which may be exerting adownward force upon the linkage 3. A coin dropped through the tube 13will move the door 14L downwardly and release the pawl 16 thus releasingthe scale beams.

'll. controlling pawl 20 is utilized in connection with the foregoingand is pivoted on a laterally projecting portion 16 of lever 16 and isarranged to engage the teeth 19 so that as soon as the weight is removedfrom the linkage 3 the rack bar and scale beam as they move upwardlywill also move pawl 20 and thus swing lever 16 on its pivot and againmove the same into engagement with the teeth 17 and prevent further useof the scale until another coin is deposited within the tube as will beseen by a comparison of Figs. 1 and 3.

The liquid within the reservoir t may be varied according to the classof service to which the scale is to be put, mercury being an example ofdesirable liquid. The evaporation of this liquid will not be appreciableand will not cause error. The specific density of the liquid, however,will vary with temperatures for which reason a highly eXpansible andcontractible metallic member 21 is provided rigidly secured at its oneextremity 22 to the scale beam and supporting at its remote extremitythe pivot pin 23 whereby the linkage 3 is supported. Thus the length ofthe respective arms of the scale beam will vary with temperature andcompensate for the variation in the specific density of the liquidwithin the resermm The somewhat modified form illustrated in Fig. 1includes the scale beam 24 tub crumed upon the bearing 25, the bearingseat as being carried by the expansible tempera ture con'ipensatingmember 27. connects the scale beam with the platforn'i or apparatuswhose weight is to be determined. The opposite extremity oi the scalebeam is bifurcated so as to include the di verging arms 29 to which thehollow cyliir drical innnersible member 30 is secured, the same beingaccomplished by the links 31. A tank or reservoir 32 receives the member30 therein and is provided with the liquid 3 01 known specific densitywhose buoyant eli'ect, acting upon the member 30, provides acounterbalancing :torce resulting in the equilibriun'i ot the scale beamA dial 3i is rotatably supported by a shaft which latter is secured atits ends as at in Fig. 5. A pointer 3'7 is secured to and carried by adrum 38 rotatablymounted upon the shaft and around which e1:- tends aflexible element 1". This flexible element -12 is connected to a weight10 and to a small float depending within the immersed member 30 orlarger float and also immersed within the liquid in the reser' voir ortank 32.

Thus when the float 30 is raised, the smaller float l4: proportionatelydescends with the lowering of the liquid level, whereby the drum 38 isrotated in a clockwise direction by the float and against the tension ofweight 40 so that the pointer 37 when read in connection with the scaleupon the dial 351- thus indicates the weight of the object producingmovement of the scale beam.

Considerable liquid must be used with this form of reservoir and forthis reason a compensating device is provided for its evaporation orchanging in level. This device includes the rotatable mounting of thedial 34 upon the shaft 35 in connection with a drum a l around whichextends a flexible element 39. This flexible element is provided with asmall weight 13 and is connect ed to the scale beam 24:, as best shownin Fig. (l, and thus to the float 30. It will be noted that the twoflexible elements d2 and 39 are extended around their respective drums38 and 11 in the same direction whereby any change in the level of theliquid in tank 32, due to natural causes ineluding evaporation, willcause a similar rotation of both the dial. and pointer 37 and thusmaintain their original relation at all times.

Thus also when the scale beam is raised, the dial and the pointer willbe rotated in respectively opposite directions and a relatively greaterdegree of movement created at the point of weight reading than ispresent in the float 30 immersed in the liquid.

AL lll'lli I claim having a graduated scale directly thereon In aweighing scale, the combination with and extending along the saidgroove, and 10 a scale beam, of a hydrostatic counterpoise connectionsbetween the said float member including a vertical tubular transparentand the scale beam.

5 liquid reservoir, a float member immersed ARTHUR SAMUEL DYSART.

in the liquid Within the said reservoir, and WVitnesses: having itssurface contiguous to the reser- C. SPENCER, voir Walls having alongitudinal groove, and JOHN LANCE.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents,

Washington, D. G. t

